I'm tempted to buy one of the new 4K TVs, but I know there's not much 4K content. How will standard and hi- def video look on one of these sets?

Frankly, 4K-TV pictures are beautiful. Also called UltraHD, or UHD, 4K televisions have a resolution of 4096 x 2160 pixels; HD is 1920 x 1080 pixels. As you point out, though, barely anyone shoots movies or TV shows at 4K resolution. What you'll be watching on your 4K set, therefore, will probably be standard-def or HD video that's been scaled up to fill in all those extra pixels. To do that, the TV stretches the data in each pixel, using algorithms to fill in the missing image information. TV manufacturers say that results in a more detailed image. However, if the algorithm's no goodif it just quadruples the size of each pixel, for instancecontent will look worse on a 4K TV.

Processors such as Sony's 4K X-Reality Pro and Samsung's Quad-Detail Enhancement can make HD content look great when scaled up, but it's harder for them to deal with standard-definition content, because there's simply less data to work with. "The upscaling is as good as the source material," says Rob Manfredo of Sony, whose 4K TVs eliminate visual noise and fill in details using an image database. The process works wonderfully with 1080p Blu-ray and 1080i satellite video, he says, but not as well with lower-resolution material, such as 480p and 720p.